End mill sharpening fixture



Oct- 2, 195l c. J. HERTLEIN END MILL SHARPENING FIXTURE Filed Sept. 3, 1948 INVENToR. 64@ d #59725//1/ Bv 4spindle and its bearing.

Patented Oct. 2, 1951 UNiTED STATES PATENT GFFICE END MiLL SHARPENING FIXTURE Carl J. Hertlein, Bronxville, N. Y.-

Application September 3, 1948, Serial No. 47,559

20 Claims. (Cl. 51-123) The invention relates in general to a work holder for mounting a piece of work relative to a tool or similar device for machining the same, and specifically relates to an attachment to a grinding machine and operative to advance and withdraw a spiral iluted end mill or similar spirally grooved tool to and from a grinding device for sharpening the cutting edges of the mill or tool.

In grinding machine attachments of this type it is known to mount the mill or tool to be ground in the recessed end of a solid spindle which in turn is mounted either directly in a rugged grinding head or in a massive bearing in turn mounted in the head. In such devices the head also carries one end of a iinger bar, the other end of which carries a guide finger which engages in the spiral of the tool to rotate the same as the tool holder is manually fed in one direction towards the grinding device. In such known devices the head is mounted for rocking movement about an axis in the longitudinal medial plane of the device and is arranged so that the spiral portion of the tool which has been rotated by the guide finger relative to the grinding surface during the feeding movement tends to leave the guide finger upon the return movement of the tool and the head is pivoted as so to turn away from the grinding surface and thereby allow the tool with its previously ground spiral cutting edge to be returned to its initial feeding position without being damaged by contacting the grinding surface of the grinder. y

In such device if the friction between the toolcarrying spindle and its bearing is too great the tool carried by the spindle of course will not rotate freely if at all, and this causes the cutting edge to be damaged by the grinding wheel and this possibility of damaging the tool will also occur if there is too much play between the Because of the close fitting between the spindle and its long bearing in known devices a little dust or emery collecting in the bearing and even the presence of a little too much oil can defeat the desired accuracy in grinding and otherwise give trouble, Further, in such known devices a great deal of heat is generated at the point of grinding and this heat is transmitted through the solid spindle to its bearing, causing variable periods of both ex- V pansion and contraction of both the spindle and its bearing with resulting difiiculty in shifting the spindle under conditions where, on the com trary, a freedom of spindle movement is vitally necessary to the proper grinding of the tool. a

` Further, in such devices the spindle wears down and its bearing is enlarged, with resulting loose ness in the desired close interiitting of the parts. No practical solution has been offered to compensate for this eventual looseness of the interd engaging parts between the tool spindle and its bearing.

Among the objects of the invention are to provide a'form of mounting for the work-carrying spindle which will tend to minimize the transference of heat to the spindle bearing; which will tend tcravoid storing of heat in solid parts of large heat storing capacity; which will provide for an extensive air-cooled area to the spindle, both exteriorly and interiorly; and which will provide for an air-cooling of the spindle mounting and associated bearing; and in which a wearing away of interengaging parts can be compensated for and the coaxial relation of the parts easily restored.

Broadly, these objectives are attained in several ways, as by forming the spindle hollow with one end open to the outside air; by mounting the spindle in a pair of spaced-apart air-cooled heads forming the top of a pair of upstanding standards also exposed for air-cooling; by supporting the part of the spindle in each head on a cradle formed of two points of limited spindleengaging area and disposed to center the spindle in its support and incidentally to form annular air spaces between the spindle and the heads and which air spaces are open at opposite ends to the cooling effect of the external atmosphere. The invention particularly features the point suspension of the tool spindle in space to minimize the frictional resistance to the desired freedom of movement of the spindle; to expose as much of the spindle as possible to the cooling eifects of the environmental air; and to utilize the rotating spindle as a blower to pass air through the free spaces between the spindle and its mounting and to sweep away any dust, dirt or other foreign matter which otherwise might tend to collect on the cradle-forming points.

Another object of the invention is to provide a form of bearing for the iinger bar, usually employed in such devices, which bearing will tend to fix the spiral-engaging finger carried by the bar rigidly in whatever place it may be set for the time being and in this way at least tend to defeat the setting up ofvibration in the finger.

The disclosure features a structure designed to provide rigidity between the finger bar and` a rugged part of the tiltable body in which the spindle is journaled. Broadly, this objective is .attained by providing in the rockable body herein featured a mounting for the finger bar which mounting will engage the bar at two widely separated points in its length; which points will be rigidly tied together by a structural part of the body and in which opposite ends of the iinger bar will be in effect Ibalanced on its support and locked thereto in such way as will tend to neutralize vibration which may be set up therein by reason ofthe rotating tool engaging the finger.

In so far' as the tiltable body isY concerned, an object of the invention is to provide an extremely strong, rigid bodycapable of functioning as re quired of such devices, but made up of the least possible amount of metal and that material distributed where it is most effective.

Broadly, this objective is attained by designing the .body for the most part asA a hollow structure, internally braced in those parts which aren intended to carry loaded or strain-resisting parts cross-section of 'materialY Still another object ofV the" invention is tofpro- Vide for an" easilymanipulated controlfor` the tilting/ofthe body, `its spindleand vthetool carried thereby-'to begro'u-nd relativet'o-'the grinding device; arranged so that simply by tilting a1 hand leverih one! direction the tool' is ybrought into proper pre-setr'elationltdthevgrinding wheelto be sharpenedtnerebygland by tilting the lever b'aclcv into its initialposition the tool is moved into an inoperative position and locked insuch position in offset relation tothe grinding wheel so.V that the tooll canbe returned freely to its initial position"v without possibility of being damaged :by the' grinding wheel;

Variousother` objects and-advantages of the invention will be'in-partobviousfrom an inspectio'nlof the acc'on'ipanyingl drawingsand in part will be more fully set forth inthe followingpar- 1 ticular descriptionof'one form of* device embodyingthe invention, land the invention also consists incertainanew andnovellfeatures of construction and" combinationof parts hereinafter set'vforth" and claimed..

In the accoinpanying'v drawings- Fig. 1- is af view inside' elevationV` partly in sectionV of an attachment constituting a preferred embodiment' of the'invention shown carryingl an end mill inposition aboutto be advanced intoengagem'ent with l a grinding wheel;

Figs.v 2il and.v 35i are each transverse sectional viewstaken, respectively, on lines 2"-2and 3-3- ofFi'g. I-lookin'g iri the direction indicated by the arrows.

In'thedrawings and-referring first to Fig. l,

thereisdisclosed'a support'A on which ismounted a'l grinding device B and an attachment C partic-v ularly forming the subject matter of this disclosure. The grinding device includes a grinding wheelD rota-ted by means of a grinding wheel shaft and includes anannular grinding face F.

The attachment carries a iiiited"l end mill C+v or side walls l if ".[liese'wallsr co'act t'o form a mutu-`I ally bracedstructure'capableof withstanding the` The bOdy' 4 strains to which such devices are subjected in use, even though the parts thereof not intended to transmit strains or to carry screws and the like are of thin cross section of material. Projecting integrally from opposite ends of the body I2 is a pair of standard forming uprights forming a forward standard I6 and a rear standard Il. Each of the standards includes a short tubularY barrel-like upper portion which forms a forward head- I8 and a rear head I9. These heads are provided, respectively, with relatively large bearing apertures 29 and 2l disposed in axial alignnient longitudinally of the device. These aperturesV do` not have to be carefully machined as they do not form bearings. Mounted in the apertures'by means hereinafter described is a long hollow steel tube open at opposite ends and providing a tool-carrying spindle 22. It is a feature ofj thisdisclosure that the spindle is exposed between the standards and at its opposite ends to thecooling. effect of. the externalair. At itsforwardend, that isat the'end nearest the grind` ing wheel, the .boref' of the spindle is fashioned to receiver the tool G or, ifl thetool is of smaller diameter than thebor'e,.to receive a tool bushing lS-in-which the small tool is fitted. At its oppo'e' site end, that is, Vthe end beyond the rear head I9; there is slidably mounted on the spindle an annular ring forming a stop collar 24 which lead--F justably'xed in place by means off a set screw 2'5. This collar isset'to limitthe feedingmove'-V nientr of the tool toward the grinding wheel D. The extremeA outer right: end of the spindle is provided with a` knurledeknob 26V secured to the spindle by'a'r screwl 27 and disposed'to be engaged by the operator in advancing the spindle and with it'the tool from right to left of Fig. l and into operative' relation to the grindingV wheel t0 be ground thereby.

The two' opposite end walls of the hollow shell 31' are provided withidenticaliopenings in longiVV tudinal axial alignment: forming two longitudinallyfspaced-apart finger bar bearings of which one' is shownat 28 in Fig. 2. These bearing forme ing" openings' have their underside in theL form of upwardly facing V-seats 29';` A long' rod-like nger'bar 30 entends through the bearings 28, projects atopposite' endsbeyond'the shellrlB, and normally rests gravitationally on the seats 29. It is the usualipracticeto'adju'st the ringer bar longitudinally to tthe different' typesy and'sizes of tools' tob'eground;v The n'g'er ba'r 391i's designed to be locked in its.longitudinally'a'djusted position and for this purpose' the portion of fthe front and top wall is thickened-as' shownin Fig; 2 to'p'rovidea gussetor boss' 3l whichtendsito brace the frontA and top walls. The boss-is provided withavertically extending opening and istl'lr-eaded to'accommodate aj set screw 325 in bearing 'engagement with the top' of" the iingerbar; The outer-end? ofthe finger bar' is'provided with an adjustable4 finger rest 33 which ntur-n carries a iinge'rY 34= for engagement-in tli'espiralHof'the tool G, as isi usual in suchd'e'vices.

The rockable body' I2 is-designed to'berocked about a longitudinally extending axis; attliefar' side of the base and for' this'V purpose there is provided a hinged mountingY 3'5`. This mountin'g includes-twol longitudinally spaced-apart pairs of recesses 36, with' one recess of each pair formed' l suture hinges of a bali bearing type en which the body may be turned. l

At the opposite or front side of the body there -is providedA an inwardly extending flange forming a lift shoulder 38, and there is provided a 'coacting body rocking device 39 for engaging the flange to elevate the front side of the body. For I"this purpose the base is drilled transversely from jits forward side to form a cylindrical form of lever bearing 40. A lever of L-shaped form provides at the front of the machine an upstandv'ing handle 4I for rocking the lever and provides a cam rod 42 rotatable in the drilled bearing 40. The cam rod 42 at the part thereof just be- -low the flange 38 is flattened on one side to provide a two-throw cam 43. A vertically extending lift pin 44 slidably guided in the base engages at its lower end and bears on the cam 43 and engages at its upper end the underside of the flange 38. A dowel pin 45 demountably fixed in the base engages in an annular recess 46 formed in the rod 42 to permit rotation but to defeat axial movement of the lever.

There is shown a resilient re-set device 41 for restoring the body I2 to its normal inoperative position when permitted to do so by the rotation of the cam 43 with its flat side uppermost as shown in Fig. 2. To accommodate the re-set device the portion of the top and rear Wall at the center thereof is `cast with a block-like thickened wall 48 forming a gusset as shown in section in Fig. 2 and in front elevation in ghost outline in Fig. l. The thickened portion 48 is drilled through the top wall I4 to provide at the bottom of the wall gusset 48 an aperture 49 and thereabove with the upper portion of the drilling enlarged to provide a pocket 59. The bottom of the pocket forms an upwardly facing spring bearing shoulder I. Extending through the pocket and aperture and in threaded engagement with the base is a headed screw 52. A spring 53 is located between the head `of the screw and the shoulder 5I and is biased in a tendency to maintain the flange 38 of the body in bearing engagement with the lift pin 44 in all positions of the same.

In this way spring 53 is operative at all times to maintain shoulder 38 in bearing engagement with lift pin 44. With the lift pin engaging the flat lobe side of the cam and in which position the handle 4I is vertical, the body I2 is at the extreme left end of its arc of swing as viewed in Fig. 2, and in this position the tool is clear of the grinding surface F and can be withdrawn longitudinally without contacting the grinder. In this way the lever handle 4I when upstanding is an indication that the tool is free to be returned to its initial grinding position. On the other hand, when the lever is tilted one Way or the other from its upstanding position it signals the fact that the tool has been swung into position so that when axially advanced it will be in proper relation to the grinding device to have its cutting edge ground thereby. Differently expressed, the throw of the cam when shifted to bring its round portion under the pin 44 will accurately locate the tool in proper position to be ground. By simply replacing the lever currently in use by another having a different cam throw the grinding position of the tool may be re-set as desired.

The spindle 22 is located to rest on a cradle formed by two pairs of upwardly extending cradle-forming pins of which two of the pins are shown at 54 and 55 in Fig. 3. Each set of cradleforming pins is associated with a vertically extending hold-down pin 56, so that at ch head there are three centering pins. 'I'he pins -are mounted in their associated heads I8 and I9 to extend circularly spaced apart and are slidably mounted in radially extending bores or sockets 51 in which they are movable with a sliding fit, and the outer ends of which pins project beyond the heads so as to provide finger piece ends 58 for engagement by the nger of the operator when adjusting the pins as hereinafter described. More accurately defined, the two cradle-forming pins 54--55 each forms an angle of fortyfive degrees with a vertical passing through the axis of the centered spindle 22, and pin56 is spaced from each of the pins 54 and 55.

The pins are each provided at their inner ends with hard bearing points 59 with their exposed portions of semispherical form and, in the instant case, formed of Carboloy. It is the intent here to mimimize as far as possible the areas of contact between these bearing pins and the outer surfaces of the spindle 22 slidable and rotatable. thereon. i

For the purpose of accommodating the structure to receive spindles of different external diameters it is suggested that each of the bearing pins be adjustable radially in their associated heads. For this purpose the lower or cradleforming pins 54 and 55 of each set are provided on the sides thereof with a plurality of longitudinally spaced-apart conical screw-receiving recesses BI. Each head is provided inthe plane of the bearing pins with a plurality of recesses 68, one for each bearing pin, each extending at right angles to the length of its associated pin and exposed at its outer end. A pair of conepointed screws 62 arerscrewed into the recesses associated with the cradle pins in position to have their pointed ends inserted selectively into one of the recesses 6I. The recesses 6I are variably spaced apart longitudinally and are arranged so that when the four screws 62 engage in the proper recesses, as for instance in the innermost recesses as shown in Fig. 3, the four bearing points 59 will define the surface of a true cylinder, hereinafter sometimes referred to as a cylinder of reference, and thus the pins will act to nx the axis of the tool spindle 22 relative to the fixed grinding device. l i

In the case of each of the hold-down pins 56, a flat screw 63 is threaded into the associated recess 68 and is disposed to bear transversely on the hold-down pin 56 to lock it into whatever position it may happen to come by reason of the diameter of the spindle for the time being mounted in the attachment.

The bearing apertures 28 and 2I are of larger diameter than the external diameter of the tool spindle `22, and thus there is formed in each head II and I8 an annular air space llropen at opposite ends to permit a free flow of cooling air to pass between the more or less warm spindle 22 and the air-cooled heads I'I and I8. Air passing the points 59 tends to clean the points.

In operation and assuming that the toOl to be ground is driven into the bore of the spindle or into the bushing 23; that the finger bar 38 has been adjusted longitudinally in the body with the nger 34 adjusted to fit in the groove of the tool spiral H; that the bar 30 has -been locked by set screw 32; and that the stop collar 24 has been adjusted on the spindle to limit the advance of the tool relative to the grinding Wheel and with the grinding wheel rotating, the operar shifts the handle 4I of the lifting lever to bring the Vtages over denotvn devices.

,unveil-or elevated portion of the @am 43 into henri; s :engagement with the lift pin t4 whioli, in gdrn, fswinss .the body I2 as a Whole ,Slightly cioe-twists about :tno offset longitudinal :axis nroridedgbvthebinaeiroounting p35 as indioatod in Eig-'12., -Slllinlil'y to bring the Cutting ,edge .I 0f the tQQl into engagement -wth ,theigrinding edge of: grinding wheel to sharpen theA Cutting edge. ifollotving ,conventional praotioes in l this .respoot- :More ooeoifioallv described, 'the .operator .engages the knob gt and shifts the spindle 22 axially and -vvi;th .-it the tool G from `right V to left in :the ,showing .in Fia .1J until the fouttne odge hasiadvancedinto engagement with and beyond the grinding pomo-11F of too grinding Whe-SL Ityvillfbe understood Ythat the engagement of xthe linger 3.4 vin the groove H ,controls the rotation ofthe spindle as itiss dviancedaxially. Atthe termination of .there ins operation, the -operator throws -the leyer ,back into the upright positionshovvn in Figs. land 2, and ,this permits the spring i3 to rook the 'body -loaok -oonntorclockwise into its normal position with ldie tool spaced to the left from the grindingfvvheeland in which lposition Athe spindle may be retracted romfleft to right of Fig. l and to its initial position .without-possiblity pf the tool contacting ,the grinding rwheelheinstant device has many practical vadvan- For instance, the loeating or .the V`hinge yconnection at the rearside and the flifvtingcam at the front side provdesa long-.leverageefect considered transversely Of the bod Lsgi/that a relatively short upward camining lothefiswingngiof the-devel" handle-til causes-a material extentiof lateral shifting of the spindle audits associateditool in moving -rom the inoperative into ,the operative position to cause the tool to `be sharpened. 4The vnormal tendency of the rtool when permitted to do so yis. to escape f rpmfthe grinding-device. vAssuming that thetool and spindle `will become ghot during the grinding operation, vevery effort is made to Withdraw the heat as promptly as possible and vdissipate it over extensive eX- posed cooling vareas and in 4 this Way keep the parts; andnortioularlv thetool,V ooo1 .Asithesoindle :is snp-portodisololv on the c -radie provided by the inner endsfpf @the vpins 5d and 55, the heat transference between the spindle and the :body is reduced in area to the Afour points forming the crowns of thesernispherical hard bearings-at-59, with perhaps some heat transference across the joints provided by the points 59 of the bearing down pins 56.`

The ends of the annnlarspacesf-are opento permitJ airfto now therethrough to thus cool both the interior of the heads lE-H, as Awellasthe portion of the spindle within the voutlines of the heads. lAs the spindle is rotagti-ngat least during Vthe grinding step, the rotating spindle will tend to act as ra blo-wer to advance the air throughthe spaces @d to perform fits cooling and scavenging functions. The spindle itself is made hollow and ofthe least possible crosssection of finaterial and, vwhile one end mus-v be closed by the tool, its other end is open through the opening in thelrnurled handle 25. Of course; someiieat Will pass by co1 i duction,. by radiation, orotherwise, inte the heads l and Il. These heads are designed Vto provide the moss .extensively possible exposed surface to the cooling7 eiect ol' the environmental air. They :extend upwardly from theassociated main body por.- tion in Widely spacedgapart relationand are made as tninasnossiblo without sacrificing thir nocessary structural strength.

il., `In :a device of the V:olado dosoribod, tno room; nina ion svi/itil o grinding device. of an -attaohnientinoludins a bano, a bodgvfnaving one sido thereof ipivotally .mounted on :the base to turn abouztlo `1t dioai anida tool-spindle iournalod'in the donor por ,fn of the vloodv for free rotary and axial :movement ond provided with Amoans Yfor oarryingfaspiral tool to loo ground, alinear liar adoustably 4moilntod in the VboC1.;v.-at two :widely s paoodfapart points .and extending parallel to tno snindle-and-nrovded atone ond With-a guide finger or engaging ,the spiral of tho tooI to be ground, said body provided on -thesido onoosite .the side pivoted tothe base -With :a ,down- Wardiy facing-shouldena liftpin-sdlidably'wmonntod for vertida- 1 movement in the body and on union tho ,Shoulder rests, Spring :means v n:acting between the bese-@Dd body tending 115.0; tlffil the .shoulder in ybearing .engagement on the litt pin, a lever with one end `forming an exposed handle :at Ytno ront of the attaonrnont and the other :end inning 'rodelike and eionrnalod :in tno body -for :rookt-rie movement about a l transvorso oXS, .and Vsaid frodelke ond ,fin the part th of iindorlannins the lift foin forming .a tivo-.throw cam and operative .as the Uhandle is `rocked in, one direction to act through vthe lift pi11 to; camth,e adiaoont Side ofthe lbody to shiftthe same up wardly -about its axis .and -to shift the spindle and rthe-toolcarried therebylaterally over an `arc Whose Center-is atthe'longitudinalaxis to vbring the tool :into Voperative engagement with :the grinding device and when .the handle fis rocked in the opposite direction to shift the cam into position to vpermit :the spring means .to irea-ct between the base and body to shift -the A tool reverseldlreotion over said arctoiremove it lfrom the grinding device.

2. In atool grinding machine, the combination of a grinding ',vvheeL of an attachment Yincludinga^base, a bodypivotal'lyfmountedto the base Zfor rocking movement about Va .longitudinal axis, spring means biased for maintaining the-body in position xed ,relative -.to the :base and ,spaced irom'ftne grinding wheel, control means 'for .engagingthefbody ior-,shiftingthe bo'dyfa'bout said axis and against the resistance of VAsaid Vspring means, said tbody .provided `with a pair of .upstanding Ispindle .bearing standardsi longitudinally spaced apartr-andfexposedor air-cooling, allong,

longitudinally exten-ding :tool spindle -journaled in both -standards Afor free manually imposed rotary and-axial movement, with substantially the entire .exterior .surface `of `the Aspindle krexposed for airs-cooling, journaling `means carried byieach standard engaging thespindle over highlyrestriotedfareas of contact, spacing thespindle from rthe--standards .and operative t0 minimize heat .transference from thespindleftothe standa-rds, .said .spindle v.having avhollow lbore extending therethrough open -at `one fend Ito .expose .its inner :sur-face io'r fiair-coo1ing and .open vat its opposite vend to provide a mounting for-:receiving theatool to be ground.

,13min a =tool grinding machine, Vthe combination Awith. a grinding device, Vof an attachment for :the mach-inev including fa f rlxed baise, a rockable Abodyrcarried thereby,Y a .pair of `standards projecting fromithelbase andrrockabletherewith, said standards being longitudinallyspaced apart to expose thesame forkairfcooling, reach of said standards provided with lan vopening extending therethrough in coaxial alignment one with the other, a tubular spindle oi cylindrical form extending through both openings and exposed for air-cooling between the standards and at opposite ends thereof, the end of the bore of the spindle adjacent the grinding device providing means for mounting the tool to be ground, the external diameter of the spindle being less than the internal diameter of the openings in the standards to provide annular air-cooling spaces between each of the standards and the portions of the spindle within their outlines, three centering pins carried by each of the standards, circularly spaced apart and extending radially of the spindle for centering the spindle in the standards, and means for mounting the body on the base for lateral rocking movement to shift the spindle and thus to bring the tool carried thereby laterally into -and out of operative engagement with the grind- `ing device.

4. In a machine for grinding spiral tools, the

'combination of a grinding device, of a tool-carrying and guiding device including a body having a pair of bearing standards projecting upwardly and integrally therefrom in longitudinally spaced-apart relation, said standards provided with coaxial cylindrical apertures, and each standard provided with a plurality of hard bearing points dening a bearing circle approximatevly centered in each aperture, a tool carrying end walls of the lower part provided with open- -ings in axial alignment, a finger bar extending through both of the end wall openings parallel to and offset from the spindle and projecting at opposite ends beyond the body and exposed for air cooling, a set screw carried by the body between its end walls and bearing on the finger bar to lock` it in longitudinally adjusted position relative to the body and to force the nger bar laterally into bearing engagement with the end walls `at the openings therein and said nger bar at the end adjacent the grinding device provided with an adjustable finger for engaging the spiral of the tool to be ground.

5. In a mechanism for holding and guiding the `spiral cutting edge of a tool and which is adapted Yto be ground by passing the tool longitudinally `along a grinder, in combination, a spindle for `holding the tool, a rockable body, means for slidably and rotatively mounting the spindle in the rbody, a guide adapted to engage the spiral cutting edge of the tool, `means for mounting the guide in the body, a supporting base, means oiset to one side of the body for rockably mounting the body to the base for movement about an axis parallel to the axis of the spindle and below the body, resilient means reacting between the base and body and biased in a tendency to rotate the body about said axis in a direction to shift the spindle and therewith to remove the tool from the grinder so as to permit thea spindle and tool to be shifted without being damaged by contacting the grinding surface of the grinder, and manually actuated camming means, reacting between the base and body and operating in one position of the camming means to form a stop for limiting the movement of the body in its non-grinding position and in another position acting against the tension of resilient means to set the spindle and therethrough to set the tool in operative relation to the grinding surface to be ground thereby.

6. In a mechanism for holding and guiding the spiral cutting edge of a tool relative to a grinding device, the combination with a grinding device, of a spindle for receiving the tool, a body in which the spindle is mounted for free and thus unrestrained rotary` and axial movement relative to the grinding device, a base for supporting the body, means hingedly connecting the body and base for relative rocking movement about a rocking axis parallel to the axis of the spindle, a spring reacting between the base and body independently of the spindle and tending normally to tilt the body and with it the spindle relative to the base in a direction to move the tool clear of the grinding device, and a manually actuated two-lobe cam in one position reacting between the base and body for rocking the body about the rocking axis against the resistance of the spring and into position to bring the tool in operative relation to the grinder to be ground thereby and in another position to permit the spring to shift the body into position to space the tool from the grinding device.

7. In a device for holding and guiding a tool having a spiral portion with a longitudinal cutting edge adapted to be ground by passing the same along a grinder, the combination of a spindle provided with means for holding the tool, a body in the upper portion of which the spindle is mounted for free rotary and axial movement, a base for supporting the body, the upper face of the base and the lower face of the body provided in offset relation to their vertical medial plane with at least one set of recesses facing each other, a ball forming a hinge element tted in the recesses and forming a hinge mounting between the bottom of the body and the top of the base, a support carried by the base on the opposite side of the medial plane and on which the bottom of the body normally rests, spring means reacting Vbody normally resting on said hinge connection and on said pin, a tool spindle carried in the upper portion of the body and laterally shiftable therewith, a, spring reacting between the body and base biased to maintain the body in resilient bearing engagement with' its two supports provided by the lift pin and hinge connection and a cam shaft rotatably mounted in the base and provided with a two-position cam, in one position acting on the lift pin to elevate the same and cause the body to rock about the hinge connection against the tension of the spring.

9. In a device of the class described, the combination of a base, a body, a tool spindle journaled in the body for rotary and axial movement, means for mounting one side of the body to the base for rocking movement about an axis parallel to the axis of the spindle, the side of the base opposite said mounting provided with a shoulder, a manually-actuated cam journaled in the base for rotary movement about an axis at right angles to the rocking axis and thus also to the axis of the spindle, a litt pin slidably mounted in the base for a limited vertical movement, the lower end of the pin resting on the cam and elevated thereby and the upper end of the pin bearing on the shoulder, and spring means reacting between the base and body and biased to maintain the spindle in a prefixed position relative to the base and to cause the shoulder to bear resiliently on the pin and therethrough to maintain the lift pin in engagement with the cam. Y Y Y 10. In a device for holding and guiding a tool having a longitudinal spiral portion with a longitudinal cutting edge which is adapted to be ground by passing the same longitudinally and retatively along a grinder, in combination, a tubular spindle adapted to receive in its bore selectively either the tool to be ground or a bushing for the tool, a body having a main lower hollow portion and a pair of solid spaced-apart standards upstanding from the main portion and provided. with openings in which the spindle is mounted for free rotary and axial movement-to and from the position where the tool engages the grinder which grinds it, the openings of said standards being substantially in axial alignment, each standardprovided on its underside with a pair oi upwardly and radially extending sockets, each extending at an angle of about forty-five degrees from a vertical plane passing through the axis of the spindle, four bearing pins, two for each standard, one snugly fitted with a sliding t-in each socket and protruding into the bore in the associated standard and said pins coacting in pairs to provide a o1r point cradle and said four pins at their inner ends provided with hard bearing points defining a cylinder of reference whose center is the center of the bore of the spindle, a pair of hold-down pins, one intruding into the top of each standard and adapted to engage the top side of the spindle to maintain the same on its cradle, and means for locking each of the pins in pre-set position.

l1. In a device for guiding an end mill relative to a grinding device to sharpen the mill, comprising a body portion, a pair of uprightV standards integral with the body portion; and the upper portions ot the standards forming relatively thin heads disposed in parallel relation and spaced part material distance and with their openings substantially in axial alignment, a mill-carrying spindle extending through the two openings, the spindle having an external diameter less than the diameter of the openings thereby to provide annular clearances between the heads and the portion of the spindle within the outlines; of the heads, each standard provided with three radially disposed spindle centering pins and with the pins of each head circularly spaced apartA and each pin projecting into. its ass-ociated annular clearance and provided at its. inner end withv a hard Ypoint of seniispherical form each providing a point contact with the spindle of limited area and operating to mount the spindle with not more than six limited-area points of engagement located in spaced relation to the standards.

l2. In a device for guiding a spirally. iluted end mill relative to a grindingy device to sharpen the longitudinal cutting edge of` the mill, the cornbination'of a base, a one-piece casting mounted on the base for rocking movement about an offset Csi i i?. longitudinal axis, said casting including an open bottom hollow shell provided at opposite ends thereof with 'a pair of rugged upstanding and longitudinally spaced-apart standards, said shell including a top and outlining side walls integrally connected, the two'end walls of the shell provided with openings forming a pair of longitudinally spaced-apart aligned bearings the lower parts of which form V-seats, a rod-like finger bar slidably mounted in said bearings, located on said V-seats with its ends projecting beyond'the shell and provided at the end'adjacent the mill with a iinger for engaging in the flutes of the end mill to rotate the same as it is shifted axially into engagement with the grinding device, screw clamping means housed within the shell and engaging the linger bar intermediate its bearings in the end walls for locking the bar tothe shell, a tool spindle journaled in the standards for rotary and axial movement and provided with means for mounting therein the mill to be ground and for centering the mill therein in position spaced from the tool spindle, and resilient means housed within the hollow shell and normally reacting between the casting and the base biased to return the casting into a position to remove the linger bar and with it the mill transversely from its operative engagement with the grinding device.V l

13. In a device of the class described, the combination with a grinding device, an attachment to the grinding device for guiding a. spirally fluted end mill relative to the grinding device to cause it to grind the longitudinal cutting edges of the mill, of a base, a one-piece casting rockably mounted in the base to turn about a longitudinal axis at the rear side of and spaced outwardly be'- youd the side of the mill nearest the grinding device, the lower portion of said casting constituting an open bottom hollow shell and the upper portion constituting a pair of integral longitudinally spaced-apart upstanding standards whose upper ends form transversely extending flat annular heads, each head provided with an opening in longitudinal alignment with its companion, a tool spindle of tubular form passed through said openings and provided at one end with means for mounting the mill therein and provided at its other end with a handle for manually advancing the spindle and its mill, a longitudinally extendingv nger bar engaging the lower hollow portion Yof the shell at two widely spaced-apart points and having a. length greater than that of theV spindle, a lock-screw carried by the upper exposed portion of the shell and bearing on the iinger rod to lock the same adiustably in position to cause its nger to engage in the utes of the millZ for than time being in the spindle, and' resilient means housed within the shell reacting between the casting and base biased to move the casting about said axis and in a direction to space the mill away from the grinding device and camm-ing means accessible from. the front side ofthe shell and` reacting, between the casting and base to move the mill against the resistance of said resilient means into position to .be acted upon bythe grinding device.

14. In a device of the class described, the combination with a grinding device, an attachment to the grinding device for guiding a spirally iiuted end mill relative to the grinding device' tocause it to grind the longitudinal cutting edge of the mill of a base, a one-piece casting' rockably mounted on the base to turnV about a longitudinal axis, saidv casting including alpair of lorigi'tudii-ialL ly spaced-apart upstanding standards each provided with an apertured head, a tool carrying tube constituting a tool spindle extending through the apertures of both heads and projecting beyond and extending between the heads and thus exposed for air cooling, said tube provided with means at the end nearest the grinding device for mounting the mill thereon and having its opposite'end open for interior air cooling, a knob at said opposite end for manually shifting the tube, and each head provided with three circumferentially spaced-apart and radially disposed centering pins with their inner ends projecting into their associated apertures, each pin provided at its inner end with a semi-spherical hard metal bearing the bearings coacting to denne a cylinder of reference of less diameter than said apertures and acting to space the tube from the heads and thus to provide an annular air space between each head and the portion of the tube within the outline of each head.

15. In a device for holding and guiding a tool having a longitudinal spiral portion with a longitudinal cutting edge ywhich is adapted to be ground by passing the same longitudinally and rotatively along a grinder by nger manipulation, the combination of a pair of spaced-apart standards each provided with an opening extending therethrough and in axial alignment, a tool-supporting spindle in the form of a tube, extending across the space between the standards and having its ends each projecting beyond its adjacent standard, said spindle-forming tube having a bore extending therethrough wide open end to end and having an internal diameter forming a large proportion of the external diameter and thus forming a substantially uniform and thin cross section of material, one end of the bore providing means for mounting therein the tool to be ground, a knurled knob pinned to the other end and located externally of the bore for nger manipulating the spindles, a stop collar slidably adjustable on the spindle between the knob and the adjacent standard, said spindle having an external diameter materially less than the diameter of the opening in the standards and centering pins carried by each standard adjustable thereto radially thereof and engaging the spindle to locate the same at least approximately centered in the openings and in spaced relation to both standards to provide annular air-spaces between the spindle and the standards.

16. In a device for holding and guiding a tool which is adapted to be ground by passing the tool longitudinally and rotatively by manual action across a grinding wheel, a spindle for carrying the tool, rockable means for supporting the tool for free operative motion and for locating it selectively either in operative engagement with the grinding Wheel or in an inoperative position spacing the tool from the grinding wheel, resilient means biased to maintain the tool normally in its inoperative position iree of the grinding wheel said rockable means including two longitudinally spaced apart standards having aligned apertures through which the spindle extends, and with the portion of the spindle between the standards exposed for air cooling, each standard provided with cradle forming means including axially shiftable pins mounted for radial movement in each standard and whose inner ends are provided with round faced bearing points of Carboloy coacting to define a cylinder of reference having exactly the external diameter of the spindle and providing a plurality of point contacts with the spindle.

17. In a mechanism for holding and guiding the spiral cutting edge of a tool and which is adapted to be ground by passing the tool longitudinally along a grinder, in combination, a grind,- er mounted for rotary movement about its axis a spindle for holding the tool, a rockable body, means for slidably and rotatively mounting the spindle in the body with its axis at right angles to the grinder axis, a guide mounted in the body and adapted to engage the spiral cutting edge of the tool, a supporting base, means for rockably mounting the body to the base for movement about an axis parallel to the axis of the spindle, resilient means at all times reacting between the base and body and biased in a tendency to rotate the body about said axis in a direction to shift the' spindle and therewith to remove the tool from the grinder so as to permit the spindle and tool to be shifted without being damagedby -contacting the grinding surface of the grinder, a stop on the base for limiting the movement of the body under load from said resilient means and manually actuated means operatively connected tothe body to rock the same away from said stop againstthe resistance of said resilient means to move the spindle and with it to move the tool at will into a manually controlled operative engagement with the grinder.

18. In a device of the class described, the combination with an upstanding standard provided on one side with an extension, said standard provided with a bearing aperture of cylindrical form extending therethrough at the extension and forming the extension into an annular ring-like head, said head provided with three circularly spaced-apart and radially extending sockets extending therethrough, the two lowermost sockets each forming an angle of about forty-ve degrees with a vertical passing through the axis of the aperture, a pair of cradle-forming pins slidably mounted. in said two lowermost sockets and having their inner ends protruding into the aperture and each of said pins provided on a side thereof and within the outline of the head with a recess and at its inner end with a spindle-engaging bearing, the head provided with a pair of cone-pointed screws, one for each of the associated recesses, and with the parts arranged so that when said screws are engaged in the recesses the bearings at the inner ends of the pins are equidistantly spaced from the aXis of the aperture, a spindle of cylindrical form mounted for free rotary movement on said bearings, and a hold-down pin carried by the head, disposed in said vertical line and acting on top of the spindle to maintain the same seated on said cradle-forming pins.

19. In a device for holding and guiding a tool which is adapted to be ground by passing the tool longitudinally and rotatively across a grinding wheel and wherein the tool is apt to become hot as an incident of the grinding operation, the combination of a spindle for holding the tool and for receiving and radiating heat received from the tool carried thereby, a one-piece metallic casting providing a support and heat radiator for the spindle, said casting including a body for the most part hollow to minimize its volumetric capacity to store heat and providing extensive heat radiating surfaces exposed to the cooling effect of the ambient air and said casting including a pair of standards integral with and upstanding from the body, each standard provided with anaperture extending therethrough and in which apertures the spindle is substantially centered, at least one of the apertures having a diameter materially assises@ 'greater than the diameter of the spindle` therein and?` forming? any annular.- air'. spacek between the spindlean'd: the wall of saidaperture, open` at` its ends to opposite: sides. of the associatedV standard', and adjustable.'v mounting means including a plurality of'pi'nscarriedby said associated standard extending' across said annular airspace and pro-- videdlat their/inner ends with bearing points for engaging the spindle;- said bearingr points being exposed` to the. cooling effects of air passing through-the airspace;

20;` Ina device of the elass` described, the combination of a' grinding Wheel having; a grinding face dening a plane of reference, a spindle for holding a toolt to be groundl Whenpassed' across sardif grinding face. a body extending` on opposite sides. of said plane of reference and in which body' theispindle' ismounted' for free axial and rotative movement,. a base for supporting the bod-35a hinge mounting: between vthebody and vbase Whose hinge axis isi parallel to and is on the side of'. thef plane ofV reference: opposite to that containing: the' axisz of the spindle, stop means on the base for: limiting ther movement of the body and Withf. it the. spindle` about the hinge axis in, the direction.A to:i move the tool carried by the spindle 16 awayf fromf. the: grinding Wheel,- a. spring reacting between thev hinge mounting and the stopl means biased. at all times to move the body into. enga-gement with theY stopy means, and' manually con:- trolled means; for rocking the body about the hinge-axis and against the resistance of the spring to bring the; tool carriedV by the spindle into a manuallyl controlled pressing engagement with the grindingwheel toV be ground thereby.

CARL J. HERTLEIN.

REFERENCES CITED The following references are 0f` record in th le ofthis patent:

UNITED STATES PATENTS Number Name Date 689,951 Clare Dec. 31, 1901 '748,651 Reimann Jan. 5,. 1904 1,323,452' Cogsdill Dec.. 2y 1919 2,035,163 Holrnberg Mar. 24, 1936 2,099,724 Cogsdill Nov. 23, 1937 Y 2,362,288v Melin rNov. 7, 1944 2,362,873 Wessman Nov. 14, 1'944 Tobias Apr. 11, 1950 

